|600-500 million years ago
|Algae, and invertebrae similar to jellyfish and worms. The firstshelled animals begin to appear in the Cambrian period. Arthopods, Brachiopods,Trilobytes
|500-440 million years ago
|Graptolites, Orthoceras, and primitive fish - the first verterbrates begin to appear.
|440-395 million years ago
|The first true plants appear. Crinoids are abundant, and eurypterids- believed to be the first air-breathing animal appears.
|395-345 million years ago
|Fish evolve into more complex animals, sharks and amphibians multiply.
|345-280 million years ago
|Ferns are plentiful and the first reptiles evolve from the amphibians.Spiders, cockroaches, scorpions appear. First animals to live on dry land.
|280-225 million years ago
|Reptiles become abundant. Trees similar to the pine develop, trilobytes become extinct.